Plunger-switch.



B. S. MQLARN.

PLUNGER SWITCH. APPLICATION mum 111113.16. 1909.

Patented Sept. 17, 1912.

\nventor flttg.

Witnesses:

n'nrrm) s'rarnsfrarnnr onrion.

iii. MGLARN, OF NEW YORK, N. 1., ASSIGNOB T0 WESTERN ELECTRIC COMPANY,

'PLUNGEH- Specification of Letters latcnt.

ESYITCH.

Patented Sept. 1'2, 1912.

application filed March 16, 1909. Serial No. 483,858.

To all whom it may concern:

Be it known that I, Ennnsr ,Q. MCLARN, citizen of the United States, residing at New York, in the county of New York and State of New York, have invented a certain new and useful Improvement in Plunger- Switches, of which the following is a full, clear, concise, and exact description.

My invention relates to electrical keys. Its object is to provide a simple, substantial and efiicient key structure.

By my invention I have provided a key structure wherein the'plunger which actuates the springs, or switching element may be readily removed and replaced; said plunger when in place being longitudinally movable between substantial limiting stops,

and also free to rotate so that it may present I new contact surfaces to the parts against which it bears and thereby distribute the wear and prolong the operative life of the device.

My invention may be more readily under-j in section, showing my invention as applied or guide for a plunger 11.

to a nonlocking key, and Fig. 3 is an elevation showing a plunger adapted for use with the key of Figs. 1 and 2, when it is desired to transform it into a locking key.

Similar letters of reference designate similar parts throughout the differentfigures.

Referring to Figs. 1 and 2, 1 isa frame on which switch springs 2, 3, 4, 5, 6 and 7 are mounted in opposing sets, one spring of each set terminating in a curved or inclined end 8 or 9. The upper part 10 of the frame 1 is of tubular form and serves as a mounting If it is desired that the key shall be non-locking, the plunger 11 may have a lower end formed as shown at 12 in Figs. 1 and 2. If, however, it is desired that the key shall be looking, the plunger may be formed as shown at 18 in Fig. 3. This feature, however, is too well understood by those skilled in the art to require detailed description.

The upper portion of the nates in a cap or button 14 gage with the upper edge 15 of the frame 1, when said plunger is depressed, and thereby limit the downward movement. The upper plunger termiadapted to entubular portion of the frame l is internally threaded shown at 16. pin or projection 1'? carried by said plunger makes striking engagement with the threaded portion '16 of the frame 1 if the plunger be lifted,

and thereby serves to limit the upper movement of said plunger and prevent its removal from the frame by a purely longitudinal movement. When, however, it is desired to remove the plunger, an upward unscrewing movement will cause the pin 17 to engage with the thr ads 16 and allow said plunger to be removed from the frame.

A plunger of the same or another form may then be inserted by a reverse operation. When in operative position, the plunger is, therefore, free to rotate and present any portion of its curved end to the springs with which it engages; its movement longitudinally is limited by substantial stops; and its removal and replacement may be accomplished simplyand rapidly. It will be readily understood that with the structure described, the key may be quic ny transformed from a locking to a non-locking type, or vice versa, by the more interchange of plungers of suitable form without involving dismantling, dismounting, or any modification of the parts associated with the plunger.

I have chosen to illustrate my invention as embodied in a single unit key structure of the well known. tubular type. Obviously it may readily be applied to other forms of key, as, for example, keys in which the springs are mounted transversely with respect to the plunger, keys mounted in strips or groups, and other allied devices. I'haVe also preferredtoshow the guide or mounting as threaded and the pin carried on the plunger. It is evident, however, that the reverse might be employedv Having described my invention, 1 claim:

1. In a key, the combination with a switch, of a plunger for controlling said switch, and a mounting for said plunger having an opening through which said plunger may be screwed into operative relation to said switch, and be thereafter free to reciprocate to operate the same.

2. In a key, the combination with a mountmounting being constructed to permit the insertion and Withdrawal of the plunger by a relative screwing motion. I

3. In a key, the combination with a frame having a threaded opening, of a switch, and a plunger for controlling said switch, said plunger having a part adapted to traverse said threaded opening by a screwing motion of the plunger, and said frame being constructed to permit the free longitudinal. and rotary movement of said plunger after said part has passed through the threaded openmg.

4. In a key, the combination with a switch, of a mounting, and a plunger for controlling said. switch, said plunger being freely rotatable and longitudinally movable between limits in said mounting, and said mounting being constructed to permit the insertion and withdrawal of the plunger by a-rotary motion of said plunger.

5. In a key, the combination with a switch, of a plunger for controlling said switch, a mounting for said plunger having a threaded opening, and a projection on said plunger adaptedto engage with said threaded part,

aeseyzve and after a limited engaging movement to be disengaged therefrom and rendered tree to reciprocate to actuate said switch.

6. In a key, the combination with a switch, a guideway,,a plunger therein having a limited reciprocating movement and an unlier ited rotary'movement, and locking devicescarried by said plunger and guideway constructed and arranged to permit of removal of said plunger.

*4". In a key, the combination with a switch, a guideway, a plunger therein, andwlevices carried upon said guideway and plunger adapted to initially cooperate and. after a limited relative movement to be interlocked, with the plunger free to have a limited ciprocating and a tree rotary movement, the said parts being released. only by a reversal. ot'said initial cooperating movement, In witness whereof, I, hereunto subscribe my name this 15th day of March A. D, 1909.

ERNEST S. MOLARN.

Witnesses Rosn ll. Nev/00MB, IRVING MACDONALD.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

